Two-speed drive for lathe camshafts



Jan. 10, 1950 G. E. CUTTAT 2,493,738

TWO-SPEED DRIVE FOR LATHE CAM SHAFTS Filed Dec. 28, 1946 l N VE N 70/? 660/965 Dry/79 Cuf/m ATTORNEY Patented Jan. 1 0, 1950 U NIT E D S TATE 2,493,738 I Two-SPEED nerve FORLATHE cinemas Georges Emile Cuttat, Geneva, switze'rfiahaassigner to Manufacture De Maemaesne Halit- Rhin, Haut-Rhin, France, a company of France Application Deeember 28, 19 16; serial iiaoslii In France November 7, 1944 Section 1, Public Law 690, August 8, 1946 Patent expires November 7, 1964 1 Claim.

tool changes, etc), must be effected as rapidly as possible.

Devices have, therefore, been designed, by means of which, starting from the constant velocity of the auxiliary shaft, an accelerated movement can be imparted to the main shaft, while it is possible to return to the slower velocity without any discontinuity and without stopping the organs causing the slow drive.

The present invention concerns a device of this type, offering the advantages of considerable simplicity and flexibility of operation. In this device, the endless screw shaft receives from the auxiliary shaft, alternately, a rapid and a slow speed, the latter being dependent on a free wheel drive, the transition from one to other speed being effected by a coupling organ controlled by the main shaft, and the characteristic feature of the device, according to the present invention, consists in that this coupling organ is placed on the endless screw shaft itself.

One type of embodiment of a device according to the present invention will now be described hereinafter and is represented, hereinafter, by way of example, in the appended drawing.

I designates the auxiliary shaft rotating at a constant speed; 2 is the main cam shaft of the lathe and 3 the endless screw shaft; the endless screw of said shaft engages a worm wheel 4 keyed on shaft end 5, provided with a conical pinion 5 meshed with another conical pinion l, keyed on main shaft 2. On shaft 3, a gear 8 rotates freely, driven at a high speed by gear 9 keyed on shaft i. Gear 5 can be put in gear with a coupling sheath fl, capable of sliding without turning on shaft 3.

On shaft I is also keyed a cog-wheel I2, driving, at low speed a cog-wheel i3, driving, in turn, through a conventional free wheel drive I4, endless screw shaft 3 in such a way that said shaft can be driven by gear train 9, 8 at a speed greater than that imparted to it normally bygear I3. Such free wheel drives are well known in the art.

The passage from low speed to accelerated speed is effected by means of the following organs:

On main shaft 2, a drum I5 is locked, carrying a catch it, capable of acting on the end of a lever II offering, in the region in which it pivots, an appendage I8, cooperating with a hook I9, mounted on one arm of a bell crank lever 2 I, the end of whose other arm carries a peg which cooperates with a groove of the coupling sheath, II.

A spring 22 causes the return motion of the coupling sheath. It is clear that when catch I6 meets lever I1 and pushes it towards the left, appendage l8, coming out of engagement with hook I9 releases lever 2i and sheath II, drawn by spring 22 engages gear 8. This gear 8 is thus associated with shaft 3 and drives said shaft at an increased speed, determined by gear train 8, 8. The endless screw drives worm-wheel which, through bevel gears 6, '5, causes the rotation of main shaft 2 at an accelerated'speed. Drum i5 carries another catch 23, facing in the opposite direction to catch I6 and which acts on one end of a lever 24 pivoted at 25 and articulated by its other end on sheath 5 I. The teeth of the latter separate from the teeth of gear 8, while, at the same time, hook IQ of bell crank lever 2I re-engages with appendage I8. Thus return is made to the driving of main shaft 2 by gear train I2, I3, 1. e., at slow speed.

Obviously, the device according to the present invention, can be combined advantageously with the safety devices described in the U. S. application No. 719,077 filed on December 28, 1946, now abandoned.

Having now particularly described and ascertained the nature of my invention and the man her in which the same 'is to be performed, I declare that what I claim is:

A device for temporarily obtaining in an automatic lathe with an auxiliary shaft an increased velocity of the main shaft comprising a driving auxiliary shaft rotating at a constant speed, an intermediary shaft carrying an endless screw, gearing adapted to transmit the rotation of said auxiliary driving shaft to said endless screw shaft and to impart a slow speed to the same, said gearing containing a free wheel drive allowing the free rotation of said endless screw shaft at a speed greater than said slow speed, a wheel rotatively mounted on said endless screw shaft, a gear adapted to transmit the rotation of the auxiliary driving shaft to said wheel and to impart a rapid speed to the same, a coupling member slidably but non-rotatively mounted on said endless screw shaft and cooperating with said wheel, a main shaft, gearing adapted to transmit the rotation of said endless screw shaft to the main shaft, elastic means urging the coupling member towards the coupling position adrum on the main shaft, two catches on said drum, a lever retaining the coupling member in the uncoupling position, a member acted by one of the catches and able to release said retaining lever, another lever for returning the coupling into the uncoupling position, said lever cooperating with the other catch of the drum.

GEORGES EMILE CUTTAT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

